OCEAN 492 B | Autumn 2016

Marine Sedimentary Processes: Elwha River Dam Removal Impacts

We will begin the course with a review the processes of sediment transport – the physical processes by which sediment particles are moved in the marine environment, and sedimentation in diverse shallow marine environments. We will start with methods of evaluating bed shear stress, move to resuspension of sediment particles, and then to transport as suspended load. The concept of sediment accumulation will be addressed, in terms of how deposition, erosion and bioturbation conspire to control the strata formed at particular sites. The impacts of these processes cause local and progressive changes of sedimentary characteristics in the seabed, which will be examined along fluvial dispersal systems from rivers to shallow marine settings. The connection between the seabed and benthic biology will be addressed by inviting speakers who are experts in this field. A homework problem set will be required in the first week of the course that incorporates Elwha delta data previously collected that will illustrate sediment-transport and accumulation processes

We will then familiarize students with the range of local sediment dispersal systems, evaluating the nearshore processes that have contributed to their development, and examining the anthropogenic impact on these systems. Emphasis here will be placed on the Elwha River dispersal system, discussing the oceanography of the Strait of Juan de Fuca, the geological development of the Elwha delta and associated features, the construction of the dams, and the present sedimentary system with its associated nearshore habitat. This will provide the students with the necessary background to plan and perform a short research cruise (~4 working days) on the Elwha delta. Teams of students will select different research projects relating to habitat impacts resulting from sediment dispersal of the Elwha River (e.g., projects could focus on effects of light attenuation due to plume dispersal of sediment, nearbed scour as a function of bottom-boundary layer transport, time scales of seabed deposition and benthic habitat creation/destruction, relationships between habitat and benthos in the seabed), and collect the necessary data to perform these projects.

In the weeks following the cruise, student teams will conduct their research projects with time allotted for laboratory and data analyses. In-class time will be spent on specific transport processes, environments, interdisciplinary aspects and analysis techniques that will aid the students in their projects. Tools for prediction will be discussed. Writing assignments and project updates will ensure that students are making steady progress in their research project. The end result will be a research paper that describes the existing process and discusses implications for the future.

Throughout the apprenticeship, a number of field trips are taken to experience, up close and personal, the sedimentary environments that will be discussed in lectures. The Friday Harbor Lab is uniquely situated to be within a couple hours drive from a range of river mouth and shallow coastal environments with varying degrees of human impact.

Enrollment limited to 12 apprentices. UW students earn “W” credits in this writing-intensive course. No textbook is required for this course.